Last month, France implemented one of the world's most comprehensive "lights out" ordinances. Conditions include turning off shop lights between 1 a.m. to 7 a.m., shutting off lights inside office buildings within an hour of workers leaving the premises, and waiting only until sunset before turning lights on, on building facades. Over the next two years, regulations restricting lighting on billboards will also go into effect.

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These rules are designed to eventually cut carbon dioxide emissions by 250,000 tons per year, conserve energy consumption, and cut the country's overall energy bill by 200 million Euros ($266 million).

But besides the economic and emissions benefits, France's Environment Ministry, emphasizes the need to "reduce the print of artificial lighting on the nocturnal environment."

Researchers are increasingly focusing on the impacts of so-called ecological light pollution, warning that disrupting these natural patterns of light and dark, and thus the structures and functions of ecosystems, is having profound impacts.

Some 30 percent of vertebrates and more than 60 percent of invertebrates are nocturnal, and many of the rest are crepuscular - active at dawn and dusk. All are potentially impacted by our burgeoning use of artificial light, scientists say. "We have levels of light hundreds and thousands of time higher than the natural level during the night," explains Italian astronomer Fabio Falchi, a creator of the World Atlas of the Artificial Night Sky Brightness, the computer-generated maps that dramatically depict the extent of light pollution across the globe. "What would happen if we modified the day and lowered the light a hundred or a thousand times?" That would be much worse, he concedes. But his point? "You cannot modify [light] half the time without consequences," says Falchi.

Every flip of a light switch contributes to altering ancient patterns of mating, migration, feeding, and pollination, with no time for species to adapt. From leatherback turtles, to birds, bats, moths, and even salmon, many species are affected by man-made light which can change the composition of entire communities of insects and other invertebrates.

While the ordinance will face some backlash in terms of safety and security, if we are to use night-time light more effectively, we can not only conserve energy and save money, but prevent some of the negative outcomes that artificial night-time light may have on wildlife.